The present invention relates to 1-oxoalkyl-2-isopropylnorbornane derivatives defined according to the structure: ##STR4## wherein X represents a moiety selected from the group consisting of: ##STR5## wherein the dashed line represents a carbon-carbon double bond or a carbon-carbon single bond and wherein R.sub.1 and R.sub.2 represent hydrogen or methyl with the proviso that R.sub.1 and R.sub.2 are not both methyl, and organoleptic uses thereof in perfumery.
Substances which provide sweet, herbaceous, minty, fruity, green, cucumber-like, rosy, cedarleaf-like, tobacco-like, sweaty, woody, camphoraceous, earthy and spicy aroma nuances with rosy, minty, herbaceous, dried-fruit, woody, sweaty, camphoraceous, earthy, piney, spicy, melony and fruity undertones are highly desirable in the art of perfumery. Many of the natural materials which provide such fragrances and contribute such desired nuances to perfumery compositions are high in cost, vary in quality from one batch to another and/or are generally subject to the usual variations of natural products.
There is, accordingly, a continuing effort to find synthetic materials which will replace, enhance or augment the essential fragrance notes provided by natural essential oils or compositions thereof. Unfortunately, many of the synthetic materials either have the desired nuances only to a relatively small degree or else contribute undesirable or unwanted odor to the compositions. The search for materials which can provide a more refined rose aroma or a more refined woody aroma, for example, has been difficult and relatively costly in the area of both natural products and synthetic products.
Alkyl substituted acetyl norbornene derivatives are known in the prior art for use in perfumery. Thus, U.S. Pat. No. 3,852,358 issued on Dec. 3, 1974 discloses the reaction of .alpha.,.beta. unsaturated ketones with cyclopentadiene according to the reaction: ##STR6## wherein R.sub.1 and R.sub.4 represent alkyl and one of R.sub.2 and R.sub.3 is alkyl and the other is hydrogen. Specifically U.S. Pat. No. 3,852,358 discloses the following reactions: ##STR7## wherein the cyclopentadiene results from the cracking of bicyclopentadiene according to the reaction: ##STR8##
In the reaction of our invention the cracking of the bicyclopentadiene can take place in situ in view of the structures of the reactants and the resulting reaction products.
The compound having the structure: ##STR9## which is a member of the genus of 1-oxoalkyl-2-isopropylnorbornane derivatives useful in the practice of our invention is a known compound, disclosed in Chem.Abstracts, Vol. 82, 1975, No. 16237m (abstract of Bull. Chem. Soc., Jap. 1974, 47(7), 1673-7. Compounds of the genus: ##STR10## other than the compound having the structure: ##STR11## are novel compounds. Thus, the novel compounds of our invention are defined according to the structure: ##STR12## wherein X is a moiety selected from the group consisting of: ##STR13## the dashed line represents a carbon-carbon single bond or a carbon-carbon double bond; R.sub.1 and R.sub.2 each represent hydrogen or methyl with the provisos:
(i) both R.sub.1 and R.sub.2 are not methyl;
(ii) when R.sub.1 and R.sub.2 each represent hydrogen and X is the moiety: ##STR14## then the dashed line is a carbon-carbon single bond.
Nothing in the prior art suggests the 1-oxoalkyl-2-isopropylnorbornane derivatives of our invention as being useful in augmenting or enhancing the aroma of consumable materials selected from the group consisting of perfume compositions, colognes and perfumed articles.